Present day weapon systems make wide use of a laser designator in which a forward observer visually locates a military target and then directs a coded laser beam at the target. The observer coordinates with a weapon delivery system to direct ordnance toward the target. Such ordnance would include a guidance system which would recognize the laser spot and guide the ordnance into the target. This designation activity may be carried on by ground personnel on foot or in vehicles. However, a more efficient operation may be performed with the means of scout helicopters. In prior known helicopter systems, visual scouting and location of targets exposes the entire helicopter and crew to the enemy, resulting in very high vulnerability.
Systems have been proposed in which the observer may be hidden from the enemy and the target located through a television system. In one proposal, a sight is to be mounted on a mast projecting above the helicopter rotor plane such that the aircraft could remain behind masking foliage or terrain with the mast-mounted sight projecting far enough above the television camera to locate the target. While an attractive concept, the implementation of this type of system has presented many problems. For example, it is necessary to stabilize the optical elements of the sight because of the natural movements of the helicopter. To stabilize the entire sight would require relatively heavy servo motors and the like. An alternative approach is to utilize a rigid sight with only the optical elements stabilized which could be accomplished with lighter elements.
The ruggedness required for a sight to be mast mounted above the rotating helicopter blades with the necessary stabilization raises a major problem of weight reduction since rugged, stabilized systems known in the prior art have proved to have excessive weight for this application. Additionally, it is necessary to combine the television system which provides the visual location of a target with a laser designation system to permit designation of the target after it is located. The highly collimated laser beam generally produces a very small spot and is therefore very sensitive to motion if it is to be maintained on target. Thus, very close stabilization is required.